I've had this thunderbird for the last 5 years & it's been a really long time since i heard how it sounded stock since i've just been modifying it since.
It's a good bass, the inlay free fretboard is a unique look & is one that catches the eye. It did sound good stock & i took out the electronics to have a simple on/off switch like the Nikki Sixx blackbird - i always play with the tone wide open. Weight is decent, although the neck dive can be a downfall for someone starting out on bass (I hand the bass low so there isn't much dive especially with a leather strap).
Build is solid, no cracks in body or finish flaws. With the fat neck & wide spacing it can be a bit of a stretch for those who have smaller hands so you might want to go towards the thunderbird IV burst series as the neck is slimmer & nut width is narrower. I modified this on my goth bass to match the narrowness of my precision neck & string spacing. The bass had great tone through an svt rig: everything was balanced & you could distinguish the growl, but through a small combo it's kinda difficult to get a decent tone from the pickups (depends on the amp i'd guess).
All in all if you're starting out, this is the only thunderbird i wouldn't recommend having, but if you want a sleeker look & something different from the traditional birds, by all means.
I've modified mine countless times & fixed it as well over the last five years so it doesn't really resemble its factory self anymore hahaha.